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authorGreg Kurz <groug@kaod.org>2020-10-03 13:01:52 +0300
committerMichael S. Tsirkin <mst@redhat.com>2020-10-04 10:43:03 +0300
commit0210a8db2aeca393fb3067e234967877e3146266 (patch)
tree43deeb36d07efb02ea3695934c31c2bf3ebd894d /drivers/vhost
parent37787e9f81e2e586b526ff5c29c94e4f41513e80 (diff)
downloadlinux-0210a8db2aeca393fb3067e234967877e3146266.tar.xz
vhost: Don't call access_ok() when using IOTLB
When the IOTLB device is enabled, the vring addresses we get from userspace are GIOVAs. It is thus wrong to pass them down to access_ok() which only takes HVAs. Access validation is done at prefetch time with IOTLB. Teach vq_access_ok() about that by moving the (vq->iotlb) check from vhost_vq_access_ok() to vq_access_ok(). This prevents vhost_vring_set_addr() to fail when verifying the accesses. No behavior change for vhost_vq_access_ok(). BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1883084 Fixes: 6b1e6cc7855b ("vhost: new device IOTLB API") Cc: jasowang@redhat.com CC: stable@vger.kernel.org # 4.14+ Signed-off-by: Greg Kurz <groug@kaod.org> Acked-by: Jason Wang <jasowang@redhat.com> Link: https://lore.kernel.org/r/160171931213.284610.2052489816407219136.stgit@bahia.lan Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/vhost.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b45519ca66a7..c3b49975dc28 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1290,6 +1290,11 @@ static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
vring_used_t __user *used)
{
+ /* If an IOTLB device is present, the vring addresses are
+ * GIOVAs. Access validation occurs at prefetch time. */
+ if (vq->iotlb)
+ return true;
+
return access_ok(desc, vhost_get_desc_size(vq, num)) &&
access_ok(avail, vhost_get_avail_size(vq, num)) &&
access_ok(used, vhost_get_used_size(vq, num));
@@ -1383,10 +1388,6 @@ bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
if (!vq_log_access_ok(vq, vq->log_base))
return false;
- /* Access validation occurs at prefetch time with IOTLB */
- if (vq->iotlb)
- return true;
-
return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
}
EXPORT_SYMBOL_GPL(vhost_vq_access_ok);